This proposal for the support of interdisciplinary research projects involving members of the Hematology and Infectious Disease Sections, Department of Medicine, Baylor College of Medicine, The Hematology Section of the University of Texas Medical School at Houston, and members of the Chemical Engineering Department at Rice University. The objective of the proposal is to determine the effects of physical stresses on the blood. The specific elements of the blood to be studied include platelets, where there will be determinations of the effects of physical stresses on the anatomic and metabolic integrity of platelets and rheological analysis of the influence of platelets on clot formation: the effects of physical stresses on the various coagulation factors on the rheological characteristics of forming clots. The effects of physical stresses on leukocytes will likewise be analyzed in order to determine the resistance of leukocytes to various forms of physical stress, and also to determine the character of functional abnormalities which develop in exposed leukocytes.